A heap-based buffer over-read issue was discovered in the function sec_merge_hash_lookup in merge.c in the Binary File Descriptor (BFD) library (aka libbfd), as distributed in GNU Binutils 2.31, because _bfd_add_merge_section mishandles section merges when size is not a multiple of entsize. A specially crafted ELF allows remote attackers to cause a denial of service, as demonstrated by ld.